This invention relates to umbrellas, and in particular to a device for protecting an umbrella against wind damage.
Umbrella design is typically driven by the requirement that the umbrella must be light in weight, and commonly used umbrella structures are relatively flexible. For this reason many umbrellas, particularly those of the collapsible kind, have a tendency to collapse from the inside out in response to excessive wind loads.
There have been a number of previous approaches to improving the resistance of an umbrella to inversion, as described in the following U.S. Patents:
______________________________________ Desarno 4,300,582 Todorovic 3,042,055 Wendorf 3,032,047 Vila 2,465,140 Grissel 2,114,598 Illoway 597,717 Horton 161,962 Gossip 122,453 ______________________________________
These patents disclose various types of reinforcing cords, tapes or the like designed to resist the tendency of an umbrella to invert when subjected to a high wind load. In all of these patents other than the Desarno and Todorovic patents, the cord or tape is placed in the plane of the canopy. This arrangement provides disadvantages as described below. In the Desarno patent the cord is placed radially inward of the canopy. However, the cord is secured both to the canopy and to the ribs of the umbrella. This arrangement is not well-suited for a fixture that can be retrofitted easily to an existing umbrella, and it restricts movement of the canopy when the umbrella is folded.
The present invention is directed to an improved device for protecting an umbrella against inversion, which strengthens the umbrella against inversion without interfering with normal movement of the canopy, and which, in the preferred embodiments described below, can easily be retrofitted to an existing umbrella.